<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Hello React</title>
  </head>
  <body>
    <div id="root"></div>
    <div id="app"></div>

    <!-- 加载React -->
    <script
      src="https://unpkg.com/react@18/umd/react.development.js"
      crossorigin
    ></script>
    <script
      src="https://unpkg.com/react-dom@18/umd/react-dom.development.js"
      crossorigin
    ></script>
    <!-- babel -->
    <script src="https://unpkg.com/babel-standalone@6/babel.min.js"></script>

    <script type="text/babel">
      // jsx => 普通javascript代码 => babel

      // React18之前:
      // ReactDOM.render(<h1>Hello World</h1>, document.querySelector('#root'))

      // React18之后:
      const root = ReactDOM.createRoot(document.querySelector('#root'))
      root.render(<h1>Hello World</h1>)

      // const app = ReactDOM.createRoot(document.querySelector('#app'))
      // app.render(<h1>Hello React</h1>)
    </script>
  </body>
</html>
